Gross Examination and Dissection
The objective of gross examination and dissection is to prepare the specimen for histologic sectioning. This typically includes describing the physical appearance of the tissue; measuring it; orienting the tissue as clinically indicated; and possibly cutting the tissue into smaller, more manageable pieces. All types of tissues submitted to the pathology laboratory undergo some type of gross examination and/or dissection prior to tissue processing into paraffin. The remainder of this discussion is focused on gross examination and dissection of a globe.
Dissection of a globe includes opening it in such a way as to display as many of the pathologic changes as possible on a single slide. Before gross dissection, the globe is transilluminated with bright light. This helps identify intraocular lesions such as tumors, which block the transilluminated light and cast a shadow (Fig 2-3A). The shadow can be outlined on the sclera with a marking pencil (Fig 2-3B). This outline can then be used to guide the dissection so that the center of the section includes the maximum extent of the area of interest (Fig 2-3C–E).
Most eyes are cut so that the pupil and optic nerve are present in the same section, called the pupil–optic nerve (PO) section. The meridian, or clock-hour, of the section is determined by the unique features of the case, such as the presence of an intraocular tumor or a history of previous surgery or trauma. In routine cases, globes with no prior surgery or intraocular neoplasm are typically opened in the horizontal meridian, which includes the macula in the same section as the pupil and optic nerve (Fig 2-4). Globes with a surgical or nonsurgical wound should be opened such that the wound is perpendicular to, and included in, the PO section. Globes with intraocular tumors are opened horizontally, vertically, or obliquely to place the center of the tumor, as outlined by transillumination, in the PO section (Video 2-1).
Gross dissection of the eye.
Courtesy of Ralph C. Ea gle Jr, MD.
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The globe can also be opened coronally with separation of the anterior and posterior segments, allowing a clinician’s view of posterior segment pathology.
Excerpted from BCSC 2020-2021 series: Section 4 - Ophthalmic Pathology and Intraocular Tumors. For more information and to purchase the entire series, please visit https://www.aao.org/bcsc.